hab mal kurz gegoogelt:

"The Navitimer for the first time, a watch featured a "navigation computer" capable of executing every calculation a flight plan requires. These include: multiplication, division, calculating ground speed, calculating miles per hour, calculating miles per minute, calculating fuel consumption, calculating rate of climb or descent, calculating the distance of climb or descent and nautical and statute mile conversion."

Flugnavigation per Rechenschieber hat man doch zuletzt zur Zeit des roten Barons betrieben nette Spielerei aber sonst..